The aquatic environment is full of places to hide, if you know where to find them. Weed beds, rocky crevices, and even the substrate are all used by fish as hiding places. A good shelter is a valuable commodity and fish behave in a much more relaxed fashion if they know that such a refuge is nearby, often moderating their feeding patterns in order to stay close. In the wild, many fish species remain in one particular area for most of their adult lives. There are many reasons for this, but one of the most important is that staying in a familiar place is a safe option because if a predator shows up, the fish will know exactly what refuges are available and where to find them quickly.

Do fish use the substrate as a refuge?

Hiding beneath the substrate is one type of refuge favored by eels and slender-bodied fish such as loaches. If danger threatens, a sudden dart can carry the fish into the bottom sand or mud considerable amount of the day partially submerged, with only their heads showing.The added bonus is that as well as avoiding their predators, this strategy conceals them from the small animals that form their own diet and acts as an ideal place from which to mount an ambush.

What happens if there is nowhere to hide?

Many fish improvise if they find themselves in a featureless environment, such as a bare aquarium. Some catfish seem to find reassurance by achieving contact with as many surfaces as possible, and may squeeze themselves into the corners or, if there are a few catfish, they may cluster together. This can happen even if a few basic shelters are provided. If they are too large, all the catfish may be found together under just one, again achieving the maximum amount of contact between their bodies and another surface, in this case other fish.

Do fish shelter in other underwater structures?

Just about any underwater formation can provide a gathering place for fish, be it natural structures such as aquatic plants, tree roots, and crevices in rocks, or even discarded litter, such as an old bicycle. The reason is that open water is a dangerous place to be. Being larger than their prey, predators can usually out swim them, but in a structured environment the smaller prey can outmaneuver their pursuers and squeeze themselves into gaps too small to admit the hunters. By assembling at such places, prey fish give
themselves the best chance of avoiding danger — so long as they do not choose to gather at a predators favorite hideout

Can fish hide in turbid water?

After rains and during stormy weather even the clearest waters very often fill with fine, suspended mud and detritus, which drastically reduce visibility. For diurnal fish predators accustomed to hunting by sight in these clear waters, the inability to see their prey is a real handicap. It means that these turbid waters are a real boost to young fish, in particular; concealing them from predators and allowing them to feed uninterrupted.